Schizophrenia in mental retardation: clinical features.

Schizophrenia is a small but important aspect of the psychiatry of mental retardation. In this article the literature is reviewed and the clinical features, symptomatology, and diagnostic parameters are discussed. Data are presented about prevalence rates, degree of mental retardation, male: female distribution, and age of onset. There appears to be no specific relationship with epilepsy or chromosomal abnormalities, although paranoid syndromes are often associated with disorders of hearing and vision. Differential diagnosis is considered and treatment approaches outlined.